| Backgroud BPA(Bisphenol A, BPA),as a kind of environmental endocrine disrupting chemical(EDC),is the main monomers in the industrial synthesis of polycarbonate and epoxy resin,and is widely used in manufacturing of baby bottles, food and beverage packaging material, the human daily life supplies, medical equipment and thermal paper. As the demand increasing, BPA has become one of the high yield chemicals in the world. In case of acid, alkali or heating cases, BPA will be released from these items. BPA can enter human body by the rutine of the gastrointestinal, respiratory and skin, and so on. Population survey shown human has been widely exposed to the environment of BPA. BPA has weak estrogen activity, can produce adverse effects on the endocrine, nerve behavior, reproductive development, and threat seriously to human health. In recent years, the study found that maternal BPA exposure to children was born in the perinatal period had significant effect on the immune function, such as the change of CD4 + T cell subgroup helper T cells(help T cell), Th1 and Th2 balance, reduce the regulatory T cells(T regulation cell, Treg cells), etc. But There are little report about intervention studies on BPA developmental immunotoxicity. Vitamin D(Vit D) is an necessary vitamin for growth and development of body. Studies have shown that Vit D also play an important regulating role in the immune response. So far, The effect of Vit D on decrease in Treg cells of offspring caused by perinatal period maternal BPA exposure remain unclear.Objective Investigate the effects of different dose Vit D supplement on splenetic Treg cells number decrease, FOXP3 m RNA expression downregulation, seruminterleukin-10 content reduce, IL 1 and tumor necrosis factor-α(TNF-α) content elevation of postnatal offspring induced by perinatal maternal exposure to BPA.Methods 8 weeks-old ICR female and 9 weeks-old ICR male mice were adaptive fed for a week in SPF animal room, then were mated and it is identified as conception when vaginal plug was found. The pregnant mice were randomly divided into blank control group, vehicle control group, 1000 n M BPA exposure group, 1000 n M BPA + 0.25 μg/kg Vit D group, 1000- n M BPA + 1 μg/kg Vit D group, 1000- n M BPA + 4 μg/kg Vit D group. The maternal mice were exposed to BPA via drinking water since the gestation day 0(GD0) to their offspring postnatal day 21(PND21), at the same time every day by intraperitoneal injection given different doses of Vit D. On PND21 and PND42, peripheral blood of offspring mice was collect and detect serum IL- 10 and IL – 1,TNF-αcontent using enzyme- linked immunosorbent assay(ELISA). Then kill the offspring mice and take the spleen sterilely, part of spleen were made into cells suspension and determine Treg cells number using flow cytometry(FCM), other parts used to extract m RNA and analysis m RNA expression level of Foxp3, a specific transcription factor of Treg cells, in real time- polymerase chain reaction(RT- q PCR). Experimental results were statistical analysis with SPSS 13.0 statistical package.Results1. General situation During the whole experiment, each group of pregnant mice were in good condition, and no abortion, stillbirth and death was observed. There was no statistical significant difference in the body weight growth of female mice between all groups during pregnancy. No statistical significant difference in the average litter size and body weight of offspring mice between groups from birth to weanling. Except for 1000 n M BPA group was higher than the blank control on PND42(P<0.05), there were not different statistically between other groups in body weight of offspring mice.2. Effect of Vit D supplement on splenetic Treg cells number decrease of postnatal offspring induced by perinatal maternal exposure to BPAMaternal intake 1000 n M BPA by drinking water in the perinatal period could caused decrease significantly in spleen Treg cells number of offspring mice. There was significant difference in spleen Treg cells of offspring mice between 1000-n M BPA exposure group and blank control group on PND21(P< 0.01), there was no significant difference among various group on PND42. Vit D supplement over the same time have certain improvement effect on splenetic Treg cells number decrease of postnatal offspring induced by perinatal maternal exposure to 1000 n M BPA, and there was a dose-effect relationship. On PND21, spleen Treg cells decrease in offspring mice started with significantly improvement at the median dose Vit D supplement group. On PND42, there were no significant difference in spleen Treg cells of offspring mice among various group.3. Effect of Vit D supplement on splenetic Foxp3 mRNAexpression downregulation of postnatal offspring induced by perinatal maternal exposure to BPAMaternal intake 1000 nM BPA by drinking water in the perinatal period could caused downregulate significantly in spleen Foxp3 m RNAexpression of offspring mice. There was significant difference in spleen Foxp3 m RNAexpression of offspring mice between 1000- n M BPA exposure group and blank control group on PND21(P< 0.01), there was no significant difference among various group on PND42. Vit D supplement over the same time have certain improvement effect on splenetic Foxp3 m RNAexpression downregulation of postnatal offspring induced by perinatal maternal exposure to 1000 n M BPA, and there was a dose-effect relationship. On PND21, spleen Foxp3 m RNA expression downreglation in offspring mice was significantly improvement at the high dose Vit D supplement group. On PND42, there were no significant difference in spleen Foxp3 m RNA expression of offspring mice among various group.4. Effect of Vit D supplement on serum IL-10 contents of postnatal offspring induced by perinatal maternal exposure to BPAMaternal intake 1000 nM BPA by drinking water in the perinatal period could caused reduce significantly in serum IL-10 content of offspring mice. There was significantdifference in serum IL-10 content of offspring mice between 1000- n M BPA exposure group and blank control group on PND21(P < 0.01), there was no significant difference among various group on PND42. Vit D supplement over the same time have certain improvement effect on serum IL-10 content reduce of postnatal offspring induced by perinatal maternal exposure to 1000 n M BPA, and there was a dose-effect relationship. On PND21, serum IL-10 content reduce in offspring mice was significantly improvement at the high dose Vit D supplement group. On PND42, there were no significant difference in serum IL-10 content of offspring mice among various group.5. Effects of Vit D supplement on serum IL-1 and TNF-αcontents of postnatal offspring induced by perinatal maternal exposure to BPAMaternal intake 1000 nM BPA by drinking water in the perinatal period could caused elevate significantly in serum IL-1 and TNF-αcontents of offspring mice. There was significant difference in serum IL-1 and TNF-αcontents of offspring mice between 1000- n M BPA exposure group and blank control group on PND21(P < 0.01), there was no significant difference among various group on PND42. Vit D supplement over the same time have certain improvement effect on serum IL-1 and TNF-αcontents elevation of postnatal offspring induced by perinatal maternal exposure to 1000 n M BPA, and there were dose-effect relationship. On PND21, serum IL-1 content elevation of postnatal offspring started with significantly improvement at the median dose Vit D supplement group, serum TNF-αcontent elevation in offspring mice was significantly improvement at the high dose Vit D supplement group. On PND42, there were no significant difference in serum IL-1 and TNF-αcontents of offspring mice among various group.Conclusions1. Maternal intake BPA by drinking water in the perinatal period could decrease in spleen Treg cells number, downregulate in spleen Foxp3 m RNAexpression, reduce in serum IL-10 content, elevation in IL-1 and TNF-αcontents of postnatal offspring mice.2. Vit D supplement over the same time have certain improvement effects on splenetic Treg cells number decrease, splenetic Foxp3 m RNAexpression downregulation, serum IL-10 content reduce, serum IL-1 and TNF-αcontents elevation of postnatal offspring induced by perinatal maternal exposure to 1000 n M BPA.3. Supplement appropriate doses of Vit D in the perinatal period may increase the number of Treg cells or(and) improve its function, thus produce certain inhibition effect of developing immune toxicity caused by environmental BPA exposure. |
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